The mobile Water vapor Aerosol Raman LIdar and its implication in the framework of the HyMeX and ChArMEx programs: application to a dust transport process
The mobile Water vapor Aerosol Raman LIdar and its implication in the framework of the HyMeX and ChArMEx programs: application to a dust transport process
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移动式水蒸气气溶胶拉曼激光雷达及其在 HyMeX 和 ChArMEx 项目框架中的应用：在粉尘输送过程中的应用
DOI：
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发表时间：
2013
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通讯作者：
J. Totems
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作者：
P. Chazette;F. Marnas;J. Totems
抽象的。水和气溶胶循环在环境应用中的耦合日益重要，因此需要能够同时测量气候学和气象学研究中这两个基本过程的观测工具。为此，在国际HyMeX和ChArMEx计划的框架内开发并实施了一种新的移动式拉曼激光雷达，WALI(水蒸气和气溶胶激光雷达)。本文介绍了这种新装置的主要特性及其在科学研究中的首次应用。激光雷达在354.7 nm的紫外线范围内使用人眼安全的发射，以及一套紧凑的折射接收望远镜。从气球或飞机上进行的水汽探测与激光雷达测量的交叉比较表明，导出的水汽混合比(WVMR)具有良好的一致性。偏差一般小于0.5g kg−1，因此在相应仪器的误差范围内。对WVMR反演的不确定度进行了详细的研究，其值在7%到11%之间，这在很大程度上受到激光雷达定标质量的限制。这也证明了激光雷达能够在白天测量大约1公里的范围内的WVMR。此外，WALI系统还提供气溶胶光学特性的测量，例如激光雷达比(LR)或颗粒去偏振率(PDR)。在2012年10月巴利阿里群岛上空的一次沙漠尘埃气溶胶事件之后，介绍了解决HyMeX和ChArMEx方案主要目标的科学应用的一个重要例子。这次沙尘入侵可能对法国西南部和西班牙地中海沿岸发生的强烈降水产生了重大影响。在这次事件中，测得的LR和PDR值分别在~45-63±6和0.10-0.19±0.01sr范围内，代表了沙尘气溶胶的特征。尘埃层还与显著的WVMR有关，即在4至6.7g kg−1之间。
Abstract. The increasing importance of the coupling of water and aerosol cycles in environmental applications requires observation tools that allow simultaneous measurements of these two fundamental processes for climatological and meteorological studies. For this purpose, a new mobile Raman lidar, WALI (Water vapor and Aerosol LIdar), has been developed and implemented within the framework of the international HyMeX and ChArMEx programs. This paper presents the key properties of this new device and its first applications to scientific studies. The lidar uses an eye-safe emission in the ultraviolet range at 354.7 nm and a set of compact refractive receiving telescopes. Cross-comparisons between rawinsoundings performed from balloon or aircraft and lidar measurements have shown a good agreement in the derived water vapor mixing ratio (WVMR). The discrepancies are generally less than 0.5 g kg−1 and therefore within the error bars of the respective instruments. A detailed study of the uncertainty of the WVMR retrieval was conducted and shows values between 7 and 11%, which is largely constrained by the quality of the lidar calibration. It also proves that the lidar is able to measure the WVMR during daytime over a range of about 1 km. In addition the WALI system provides measurements of aerosol optical properties such as the lidar ratio (LR) or the particulate depolarization ratio (PDR). An important example of scientific application addressing the main objectives of the HyMeX and ChArMEx programs is then presented, following an event of desert dust aerosols over the Balearic Islands in October 2012. This dust intrusion may have had a significant impact on the intense precipitations that occurred over southwestern France and the Spanish Mediterranean coasts. During this event, the LR and PDR values obtained are in the ranges of ~45–63 ± 6 and 0.10–0.19 ± 0.01 sr, respectively, which is representative of dust aerosols. The dust layers are also shown to be associated with significant WVMR, i.e., between 4 and 6.7 g kg−1.